Regulator



J. E. BEvlNs REGULATOR vFiled 4July 18,y 1944 2 Sheets-Sheet 1` A TroRA/EY y July z, 194s.4 q.. EBEWNS -2,403,332

REGULATOR Filed July, 1'8, 1944 .2 sheetsfsneet 2;.

INVENTOR. Y Tallies .BevL'JLS Y A TTORNEY Pennisi July 2, 194e.

ortica REGULATOR James E. Bevins, Hackensack, N. J., assignor to Bendix Aviation Corporation, a corporation of Delaware `Tetei-boro, N. J.,

Application July 1s, 1944, seriniNo. 545,491

(cl. 23o- 11) 8 Claims.

This invention relates to supercharger regulators and particularly to supercharger regulators ,for aircraft cabins.

In the operation ofaircraft, particularly at high altitudes, it is customary to-provide the aircraft with a sealed cabin and to supply the cabin with air in such a manner that the pressure and rate of flow of the air to the cabin is controlled at all times.

One of the objects of the present invention is to provide a regulator to maintain a predetermined rate of flow of air to the cabin at any altitude and at any engine speed between cruising and maximum R. P. M;

Another object of the present invention is to provide la regulator so constructed and arranged as to automatically render the supercharger highly responsive to changing conditions while at the same time infallibly retaining full stability of control.

Another object of the invention is the provision of the lightest possible reliable device,- which utilizes the balancing of opposing forces and the use of follow-up pressures instead od distances An important object of the invention is to provide a regulator of the foregoing described character which is so constructed and arranged as to constantly maintain a desired rate of flow of air to the cabin through the medium oi' pressure-sensitive elements.

Another important object of the invention is to provide a regulator of the foregoing described character which is equipped with means' for preventing the maintenance of excessive ratesof iiow of air to the cabin.

A further object of the invention is w provide n regulator of the foregoing described character which is simple'in construction, durable in use,

eiilcient in operation, economical in manufacture,

relatively light in weight and extremely compact to lise Other objectsand advantages wil1lbe'apparent 4from a perusal ofthe specification, a study of the claims and an inspectionofthe annexed draw- I drives the external 2 ring gear 2 of a planetary l drive having a sun gear 3 driven by planet gears .when its flow 4is throttled, imposes a 5. vA shaft C connects the a gear pump brake 1 which, driving torque 4 pivoted on a spider spider I with a gear in 'which is proportional to the differential pressure across the pump. The driving system, including thehydraulic circuit shown, isdisclosed and claimed in U. S. application for Letters Patent,

Serial Number 421,082, filed November 29, 1941, and which system contains valve 8 to whose cylinder pressure lines 9 and hydraulically lock the piston valve 8 in a throttling position securely 'even though valve 8 sets up a pressure drop ofV over 1000 p; s. i. between high and low pressure sides 8a and 8b, respectively. An increase in the y,air flow and hence of the Venturi pressure differential beyond a set value requires that main valve 8 move in the direction of thev arrow in Figure 1, todecrease the driving torque on the blower.

As also disclosed in the aforementioned appliends are connected cation, a supercharger or blower I I is ldriven by Referring to the drawings, wherein like reference characters designate like parts throughout the 4several views:

Figure 1 somewhat diagrammaticaliy shows. Partially in sectioned elevation, the regulator and the engine-driven superchar'ger which it controls; Figurez is a-sectional elevation through the regulator itself as preferably constructed.

As illustrated in Finire 1 4of the drawings, I

provide a driving system wherein an engine 'shaft the sun gear 3 through the medium of al shaft I2. Air drawn from the atmosphere by the blower I .I is discharged through the venturi I3. 'Ihe venturis inlet and throat pressure lines I4 and I 5, respectively, carry the pressure diii'erential to the casing I6 of the regulator R where it acts upon a diaphragm II with a force which is opposed by a spring I8.

The outer end of a rod 20 abuts, and hence moves with, the diaphragm I1, while a pilot valve 2l is attached to the inner end o f rod 20 to move in unison with the diaphragm Il. O11 under a substantially constant pressureof, e. g.. 100 p. s. i. is supplied from the hydraulic circuit by a pressure-reducing valve 22, supply line 23, and passage 24 in the casing I6 to the side of pilot valve 2| adjacent the diaphragm Il. A governingpressure port 25 is substantially covered by the pilot valve 2|, when the latter is in its. normal regulating position, and communicates with a I end of the piston member (as viewed in Figure 1), the other end being exposed" to the suction pressure of the hydraulic circuit, which is yat nearly atmospheric pressure,'by

the drain passage 30. A spring 32 abuts the lower end of the member 29 and has a deiinite length when com- Vpressed under the normal lgoverning pressure. A

a throttling pistonl I0 which, when blocked,

passage 26a carries this pressure to the side, adjacent the valve 2|, of a small' flexible sealing diaphragm 34 which is `attached to the rod 2lil i required for such regulated systems.

The high pressure side of the hydraulic circuit is connected by a pressure line 40 with a cylinder 42 in which is disposed a plunger member 44, the latter being pierced, at one end, by pin 45 which is abutted by a spring 46 whose other end is fixed. The member 44thus has a de nite position for each braking pressure and hence for each driving torque.

The opposite end of the member 44 is formed with a cylindrical sleeve 44a which is provided with ports 44b and 4 4c for cooperation with` a relay valve 41 which is a portion of the piston member 29. A passage 49 carries oil under the full supply pressure to a central opening 48 while ports 44h and 44o communicate with pressure' lines 9 and l0, respectively, for the servo-operation of the main control valve 8, as earlier described. The relay valve 41 has lands 5I and 52 respectively substantially covering ports 44h and 44o when the relay valve is in its neutral position, thus hydraulically locking valve 8 in a throttling position.

Adjacent the member 29, the casing is provided with adjustable eccentric stud-pins 53 and 54 which limit the travel of the piston member 29 and hence also the working range of theL hy draulic braking pressure. v l The description thus far applies strictly to the structure diagrammatically illustrated in Figure 1. It also generally applies to Figure 2 which shows the preferred construction that differs in several details as mentioned below. In Figure 2 a screw 60 is provided to alter the setting of the Venturi differential, an adjustment not shown In Figure 2, the plunger-piercing in Figure 1. pin 45 is shown as being prov'ldedl with a depending extension 45a which is slidably mounted in a longitudinal guide slot 45h formed in the casing 'I6 to maintain the plunger 44 and its several ports against rotation, thereby insuring registry with their respective passages. plunger member 44 is shown in Figure 2 to have its sleeve 44a attached thereto by means of a pin 44d. The sleeve 44a carries a pin 44e which extends through an. elongated slot 44f formed in the stem of piston member 29 to facilitate assembly and permit relative sliding movement therebetween.

The operation o! the regulated system is as follows, reference being had to Figure 1.

When normally regulating at the set Venturi diiierential, the main valve 8 is locked in the.

throttling -position suitablefor the engine speed,

atmospheric condition and tightness of aircraft cabin. For this locking, the' relay valve 41 is neutralized relativey to the ports 44h and 44c in the sleeveA end of the "44. The pilot valve 2l is also steadily in its normal position closing the port 25 and the normal governing pres- -sure acts on the sealing diaphragm 34 to produce a standard force partially balancing that due to the Venturi differential acting on the diaphragm Thev I1 with the result .that a lighter spring I8 is used than would otherwise be adequate.

Upon an .increase of the ow due to, e. g., a

.sudden increase ln cabin leakage-area, the increased Venturi differential forces to the left both diaphragm I1 and pilot valve 2l to partially uncover the port 25 and increase the governing pressure until such pressure creates a sufficient increase of the force on, the sealing diaphragm 34 to nearly restore the pilot valve 2l to its normal position. In the meantime, the increased governing pressure has forced the relay valve 41 towards the port 44h to partially uncover port 44o to drain and port 44h to the o il supply, thus actuating' main valve 9 in the 4direction towards the line I0 to decrease the braking pressure, driving torque, and air flow. Thus the Venturi differential is affected in the direction to restore it to the set value.. As the brake-pressure decreases,.plunger 44 is actuated by its spring 46. 'Ihis moves the sleeve containing ports 44h, and 44o in a direction to gradually neutralize the relay valve 41 and bring the main valve 9 asymptotically to its new equilibrium throttling position.

From the foregoing, it will b'e clear that a decrease of the' Venturi differential willcause regulator changes in the opposite direction: pilot valve 2| is slightly actuated toward the diaphragm l1, the relay valve 41 is moved towards the pins 53 and 54, followed in that direction by the plunger 44, main valve 3 is squeezed towards the opposite direction, with a gradual increase of the speed of the blower until the set value of Venturi differential is again reached.

In following through the operation above, it is apparent that each regulator element in turn is stabilized before the next acts fully: the relay Vvalve 2| is-stabilized by the pressure follow-up ertia acting to slow the rate of change of the.

blower speed.

'I'hesel renements make possible an extreme reduction 'oflsize of the parts, pilot valve 2l having a length and diameter of less than one-sixteenth inch and with a dead-zone of less than 0.0005 inch. A further important reduction of size and weight results from the telescoping of the parts of the relay. -Also, in this generally proportional follow-up arrangement, the resetting action, or elimination of droop or loaderror, is provided with a minimum of mechanism,

simply by the fact that cylinder 23 permits piston 29 and the port-sleeve of the member 44 to take any required position to exactly restore the Venturi differential precisely to its set value.

. Thus adequate perfomance, .as regards reliabilityyaccuracy and stability vof regulation, is provided with a striking reduction of size and weight along with completeelimination of trappy links, levers and other mechanical or kinetic follow-up devices which are sensitive to the vibration, jarring and the likevwhich occurs in aircraft operation.

While only one embodiment of the present invention has been shown in the drawings, it is to understood that various changes may be made in the construction thereof without departing from the scope of the invention Iand for this reason,

u. is intended not produce a quick proportional moved by said l to limit the invention-by the description herein given as-an example, but solely by the scope of the appended claims, noting that any diiferential producer is an equivalent to the venturi noted in the that the' any other pump-braked drive may preamble and be replaced by .suitable hydraulic motor.

I claim:

1. A regulator for flow through a venturi from a blower which is driven with the torque 'gov-- erned by a hydraulic-pressure device, comprisingfa control valve for the hydraulic fluid, a servomotor positioning said valve, servomoton means including a pilot means. for

s maintaining 'a governing pressure for said device proportional rto'the Venturi differential, a means including avspring and a piston having the piston movement proportional to the hydraulic driving torque, and a both the other means l relay upon a change in either said gove pressure or the position of said piston, said iollow-up means including a. reset means to graduthe stated correspondence, whereby, upon a sudden change of the flow through the venturi, there is -a sudden proportional change in the corresponding governing pressure and an actuation of the relay and of the reset lchange of the hydraulic., pressure followed by a slow further change in the same direction, I

2; In a regulator for ilow through a venturi from a blower which governed by a hydraulic-pressure system including a control valve for iiuid and a servomotor positioning device, for a the hydraulicl the valve, the pilot means nfor maintaining a governing pressure for said device proportionalto the'Venturi diilerential, a means including a first spring and a. plunger having 'a movement proportional pressure and hence to the driving torque, a second spring, a movable piston member axially aligned with and abutting said second spring and having one side pressureconnected with the governing pressure to proportionally compress said second spring, and a relay couple for the servomotor having one plunger and the other by said piston member, said plunger being axially aligned lwith said piston memberl andalso abutting sai second spring, whereby the relative movement o ple elements following arsudden change of the Venturi differential initially depends upon both said governing and hydraulic pressures and ultimately depends only upon sure.

3. The combination set forth in claim 2 including a pressure follow-up for the pilot means arranged to oppose the action ofthe Venturi differential upon the pilot means.

4. An instrument for regulating a first pressure to apredetermined normal value in a sysy tem in which a valve controls the flow of a iluid accompanied by a second said first pressure which is pressure which affects to be regulated, comnalforce, a spring acted upon by the diaphragm tending to convert the"I force into a proportional movement, a pilot valve diaphragm to set up a governing pressure proportional to said movement, a second diaphragm acted upon by the governing pressure and connected with the first diaphragm to to the hydraulic element positioned by said *prising a diaphragm acted upon by the il'rst pres.

sure to set up a proporti a relay for said oppose it to act as a pressure follow-up, a pis- -ton member, a passage connecting the pilot valve with one side'of the piston member, a relay valve lportion of said piston member, a ported sleeve for the relay valve with the ports located to be closed by the relay valve when the latter is in a neutral position, a spring between the relay valve and its sleeve to oppose the piston-and provide a definitel predetermined governing pressure and a plunger acted upon by thecontrolled second pressure which affects that on the first-named diaphragm,- said plunger being connected with said sleeve, whereby a sudden change oi lthe first-named pressure results in a momentary movement of the response of the said governing presber and the other ment and topredetermine the pressure in coaction with the piston member `an effect of the relay valve in a corresponding direction and a early rapid movement of the control the stated sudden change following by an asymp totic approach to a new iinal position of the control valve which accurately restoresthe llrstnamed pressure to its set normal regulating value. i

5. In an instrument forl regulating, precisely to a predetermined normal value, a physical variable in a system in whicha valve controls a pressurewhicn in a retarded manner, affects the physical variable, the combination of a first means for setting up a governing pressure propoi-tional to the value of the physical variable lto be regulated including a follow-up proportional to the. value of the governing pressure, a piston member having the governing pressure act on one end, a second means including e.. plunger for setting' up a movement of said plunger proportional tothe pressure which affects the, value of the physical motor and a relay couple for the servomotor having one element connected with said piston memwith said plunger, one of the vdouble-land piston valve and the other a sleeve having two ports which are substantially covered by the bands with said pis ton valve in its neutral position, and-a spring connecting said elements to allow relative moveelements. being a area 6. In an instrument for governing a controller for the flow of a control agent ailecting a physical variable to be measured and regulated vin a plant in which inertia appreciably retards the in the flow-rate bination of two the meter and of said control agent, the comservos in series betw'een variable, a servo including a servo-v normal governing value of said variable to a change for the ilrst servo consisting of a diaphragm connected to its relay valve and a hydraulic followup from its relay valves governed hydraulic pressure to said diaphragm, a hydraulic-flow restriction in the connection of the first servos relay valve to its servomotor to retard the action of the latter and hence of the last servo's-A relay valve to provide a substantially asymptoticl approach to a new steady positionl of the latter, and a presagent to thel sure followfup from the controlled last servos relay valve for substantially reducing stated inertia whichl would other-` wise strongly tend to produce by following a sudden change of the measurement which governs the rSt servo, the rst servo tends to asymptotically approachA and substantially reach a lnew' steady condition before trcller does, to thus provide 7. The combination set stable regulation. forthin claim 6 in the con-` instability, where which the diaphragm is resilient and the combisaid valve, and a relay for said s ervomotor, said nation includes a. hydraulic-now restriction in relay having two relatively movable parts with change of thev value of the measured variable and due tothe haltered follow-up. the rst servos relay valve moves quickly beyond the final position which it subsequently asymptotically ap- 8. A regulator for ilow vthroughV a, venturi from a blower, the speed of lwhich is controlled by a hydraulic pressure, a control valve for the hydraulic iluid,\ a servomotor floatingly positioning 20 

